GRANATELLI MAF sensor.

This is a discussion on GRANATELLI MAF sensor. within the External Engine forums, part of the LSx Technical Help Section category; Originally Posted by 666ws6
I lived the GMAF prophecy for awhile... then I got a tune and found it to ...

I lived the GMAF prophecy for awhile... then I got a tune and found it to be running me very very lean. I went back to a stock maf and whamo, ran perfect and smooth again. Big SOTP difference at WOT. My A/F ratio back in the safe zone!

I couldn't recall the actual A/F value. I have my EFI logs, but can't seem to show the AF ratio. My O2 sensor voltages at WOT were down near 0.0006 V and then once I got the stock MAF back in, I was running 0.9 V on both sides at WOT. (If that helps)

I couldn't recall the actual A/F value. I have my EFI logs, but can't seem to show the AF ratio. My O2 sensor voltages at WOT were down near 0.0006 V and then once I got the stock MAF back in, I was running 0.9 V on both sides at WOT. (If that helps)

EFI live.... booooooo.

I would love to see back to back runs. If anyone has one of these awesome, magical MAFS that they realized they were better off without.... and want to send to me we will do a cool test.... (maybe).

I will get my car tuned nicely, with my stock MAF.... then I will install your magical fairy blessed MAF and log true AFR reading's through HP tuner. Of course I would give it back, I dont want that damn thing.

I would love to see back to back runs. If anyone has one of these awesome, magical MAFS that they realized they were better off without.... and want to send to me we will do a cool test.... (maybe).

I will get my car tuned nicely, with my stock MAF.... then I will install your magical fairy blessed MAF and log true AFR reading's through HP tuner. Of course I would give it back, I dont want that damn thing.

That would be cool to see though.

This I would like to see! Hope you find somone to send it to you so we can get exact #'s.

Anybody selling a stock maf? Lol I believe this is one of the reasons my motor died. I brought the car a while back with the GMAF on it later on i did LT ORY heads cam.. then a little later on ... poped a piston and killed a valve. Engine is still await tear down to see whats up in there. But a new block will be going in .

I changed it back to stock yesterday. The noise went away, and it seems to run a lot smoother now too. Is it possible I caught it before any damage was done?

Depends... To some extent or another a lot of engines experience spark knock. Whether it is from crappy gas, poor tuning, bad parts, or whatever. How frequent and how severe are the questions.

The knock sensors are designed to pull timing when triggered, thereby helping to save an engine from detonation. You can pull the plugs and take a read on what has been going on in your cylinders. You can also use a bore scope which will allow you to inspect the top of the piston and combustion chamber.

Absent any obvious problems, you are probably ok. Other items that can help if the problem returns would be to change your fuel filter, utilize an engine cleaner (Sarge recommends AutoRx) and a fuel system cleaner such as Chevron Techron. Deposits in the combustion chamber and on the valves can all impact an engines susceptibility to knock. I assume you already utilize the proper grade of gasoline.

Yeah, I never run under 93 octane. It only made the noise at like 5500 rpms and higher before. After I put the stock sensor and housing back on, at first it didn't want to idle. After I took it down the road and back, it straightened right out. I let it idle for about 10 min. and took it out and got on it hard and it seems to have more higher end power now than it did with the gmaf. It seems smoother throughout too. And the noise I was hearing is gone. If there is any damage, shouldn't I be able to feel a miss or something?

Yeah, I never run under 93 octane. It only made the noise at like 5500 rpms and higher before. After I put the stock sensor and housing back on, at first it didn't want to idle. After I took it down the road and back, it straightened right out. I let it idle for about 10 min. and took it out and got on it hard and it seems to have more higher end power now than it did with the gmaf. It seems smoother throughout too. And the noise I was hearing is gone. If there is any damage, shouldn't I be able to feel a miss or something?

It's normal for the engine to act a little off in light of the fact that your new MAF is sending different signals to the PCM. With your old MAF, the PCM was compensating and making adjustments based upon that signal, together with its other engine sensor data. Anytime you change out parts that alter the data, the PCM has to "relearn" as it compensates for the changes. Same thing happens when you disconnect the battery. This can result in stalling, poor or loping idle, and other oddities that should go away with time.

Why would you need a dyno tune to flow more air? If I hear my air intake flowing more air then it must be doing something. The engine is basically an air pump, more air in and your freeing up more HP. The MAF is not a terrible mod, you may not like them but you cant say it is terrible.

just thought it hasnt been spelled out very clearly for some people. while the engine is an air pump, it has to have the correct air/fuel mixture for the combustion to take place properly. if you put more air in you have to add the appropriate amount of fuel to keep the proper ratio. if the engine management system cant properly compensate for the increased air flow due to its preset limitations or whatever, you need a tune to change the setup. im trying to make this simple. maybe it will help.